From 356ecce5cd196afe533d881d888856fd41fe624e Mon Sep 17 00:00:00 2001
From: Nathaniel Daniel <nathaniel.daniel12@gmail.com>
Date: Tue, 14 Jun 2022 19:38:17 -0700
Subject: Change gethostname to use a buffer of MaybeUninit values

---
 src/unistd.rs | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

(limited to 'src/unistd.rs')

diff --git a/src/unistd.rs b/src/unistd.rs
index 86eec627..6a7f0c37 100644
--- a/src/unistd.rs
+++ b/src/unistd.rs
@@ -1005,20 +1005,23 @@ pub fn sethostname<S: AsRef<OsStr>>(name: S) -> Result<()> {
 ///
 /// ```no_run
 /// use nix::unistd;
+/// use std::mem;
 ///
-/// let mut buf = [0u8; 64];
+/// let mut buf = [mem::MaybeUninit::uninit(); 64];
 /// let hostname_cstr = unistd::gethostname(&mut buf).expect("Failed getting hostname");
 /// let hostname = hostname_cstr.to_str().expect("Hostname wasn't valid UTF-8");
 /// println!("Hostname: {}", hostname);
 /// ```
-pub fn gethostname(buffer: &mut [u8]) -> Result<&CStr> {
+pub fn gethostname(buffer: &mut [mem::MaybeUninit<u8>]) -> Result<&CStr> {
     let ptr = buffer.as_mut_ptr() as *mut c_char;
     let len = buffer.len() as size_t;
 
     let res = unsafe { libc::gethostname(ptr, len) };
     Errno::result(res).map(|_| {
-        buffer[len - 1] = 0; // ensure always null-terminated
-        unsafe { CStr::from_ptr(buffer.as_ptr() as *const c_char) }
+        unsafe {
+            buffer[len - 1].as_mut_ptr().write(0); // ensure always null-terminated
+            CStr::from_ptr(buffer.as_ptr() as *const c_char) 
+        }
     })
 }
 }
-- 
cgit v1.2.3


From 22c4ba8bc0f7f9de703cf64007f5d0ef1ebdd943 Mon Sep 17 00:00:00 2001
From: Nathaniel Daniel <nathaniel.daniel12@gmail.com>
Date: Fri, 24 Jun 2022 18:29:07 -0700
Subject: Change gethostname to return an OsString

---
 src/unistd.rs | 29 +++++++++++++----------------
 1 file changed, 13 insertions(+), 16 deletions(-)

(limited to 'src/unistd.rs')

diff --git a/src/unistd.rs b/src/unistd.rs
index 6a7f0c37..01181893 100644
--- a/src/unistd.rs
+++ b/src/unistd.rs
@@ -991,37 +991,34 @@ pub fn sethostname<S: AsRef<OsStr>>(name: S) -> Result<()> {
     Errno::result(res).map(drop)
 }
 
-/// Get the host name and store it in the provided buffer, returning a pointer
-/// the `CStr` in that buffer on success (see
+/// Get the host name and store it in an internally allocated buffer, returning an
+/// `OsString` on success (see
 /// [gethostname(2)](https://pubs.opengroup.org/onlinepubs/9699919799/functions/gethostname.html)).
 ///
 /// This function call attempts to get the host name for the running system and
-/// store it in a provided buffer.  The buffer will be populated with bytes up
-/// to the length of the provided slice including a NUL terminating byte.  If
-/// the hostname is longer than the length provided, no error will be provided.
-/// The posix specification does not specify whether implementations will
-/// null-terminate in this case, but the nix implementation will ensure that the
-/// buffer is null terminated in this case.
+/// store it in an internal buffer, returning it as an `OsString` if successful.
 ///
 /// ```no_run
 /// use nix::unistd;
-/// use std::mem;
 ///
-/// let mut buf = [mem::MaybeUninit::uninit(); 64];
-/// let hostname_cstr = unistd::gethostname(&mut buf).expect("Failed getting hostname");
-/// let hostname = hostname_cstr.to_str().expect("Hostname wasn't valid UTF-8");
+/// let hostname = unistd::gethostname().expect("Failed getting hostname");
+/// let hostname = hostname.into_string().expect("Hostname wasn't valid UTF-8");
 /// println!("Hostname: {}", hostname);
 /// ```
-pub fn gethostname(buffer: &mut [mem::MaybeUninit<u8>]) -> Result<&CStr> {
+pub fn gethostname() -> Result<OsString> {
+    // The capacity is the max length of a hostname plus the NUL terminator.
+    let mut buffer: Vec<u8> = Vec::with_capacity(256);
     let ptr = buffer.as_mut_ptr() as *mut c_char;
-    let len = buffer.len() as size_t;
+    let len = buffer.capacity() as size_t;
 
     let res = unsafe { libc::gethostname(ptr, len) };
     Errno::result(res).map(|_| {
         unsafe {
-            buffer[len - 1].as_mut_ptr().write(0); // ensure always null-terminated
-            CStr::from_ptr(buffer.as_ptr() as *const c_char) 
+            buffer.as_mut_ptr().wrapping_add(len - 1).write(0); // ensure always null-terminated
+            let len = CStr::from_ptr(buffer.as_ptr() as *const c_char).len();
+            buffer.set_len(len);
         }
+        OsString::from_vec(buffer)
     })
 }
 }
-- 
cgit v1.2.3